Lawn mower barrier

ABSTRACT

A lawn mower barrier ( 3; 3 ′) for restricting autonomous lawn mowers ( 2 ) to a designated area ( 4 ). The lawn mower barrier comprises an elongate, pliable barrier body ( 5; 5 ′) with two terminal ends ( 6   a,b;    6   a′,b ′), the barrier body ( 5; 5 ′) is a fluid proof container comprising a hollow space ( 7 ); the terminal ends ( 6   a,b;    6   a′,b ′) are configured for connection to each other to form a closed loop, and the lawn mower barrier ( 3; 3 ′) comprises a valve ( 12   a;    12   b ) for filling the barrier body ( 5 ) with a fluid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase under 35. U.S.C. § 371 ofInternational Application PCT/NO2019/050196, filed Sep. 27, 2019, whichclaims priority to Norwegian Patent Application No. 20181280, filed Oct.3, 2018. The disclosures of the above-described applications are herebyincorporated by reference in their entirety

FIELD OF THE INVENTION

The invention relates to a lawn mower barrier, and more specifically toa lawn mower barrier for autonomous lawn mowers.

BACKGROUND

In order to restrict movement of autonomous lawn mowers to a designatedarea, most autonomous lawn mowers comprise a control system. Such acontrol system could be a GPS, and the autonomous lawn mowers arecontrolled to move within a designated area defined by GPS coordinates.Another means for restricting movement of autonomous lawn mowers is toplace a wire along the periphery of the designated area, and the controlsystem is designed such that the autonomous lawn mowers will not crossthe wire in the ground below it.

However, mishaps and errors can occur, and at high-risk areas such asclose to runways at airports an aforementioned control system is notenough; a physical barrier is required to prevent the lawn mowers fromaccidentally moving e.g. onto a runway in case the control systems fail.Lawn mowers generally have low clearance to the ground, but are designedto pass by humps and unevenness on the ground.

A physical barrier must be resilient enough to not collapse or move incase a lawn mower bumps into it. Different physical barriers exist, suchas fences, bricks etc, but it is difficult and time-consuming to setthem up and remove them, or even adjust them.

A physical barrier for autonomous lawn mowers may not be needed e.g.during winter, and it should therefore be easy to both install, removeand store. In the event of an accident, mishap or other extraordinaryevent near or on the area defined by the barrier, it is alsoadvantageous if it is possible to pass by the barrier in both personalvehicles as well as planes moving on the ground, without putting at riskthe passengers of the personal vehicle or airplane, and withoutcompromising the integrity of the physical barrier.

Documents useful for understanding the field of technology includes thefollowing: U.S. Pat. No. 5,720,678 A describes a hollow inflatablebarrier for sports games. A fan or blower is connected to the barrierand provides a continuous stream of air into the barrier to keep itinflated. U.S. Pat. No. 5,157,867A describes an elongate landscapeedging strip. U.S. Pat. No. 5,323,593 describes an unattended lawnmowing system with multiple lawn mowers. U.S. Pat. No. 3,540,699Adescribes a device for preventing or hindering motor vehicles from goingoff a roadway. WO2009019681A1 describes a modular barrier unit where anumber of which can be used for erecting a modular unit. US 2018/213719A1 describes a doorway system for a robotic vehicle that accesses aseparated area through a barrier.

It is therefore a need for an improved physical barrier for autonomouslawn mowers to reduce or eliminate the abovementioned disadvantages ofknown techniques. It is an objective of the present invention to achievethis and to provide further advantages over the state of the art.

SUMMARY

In an embodiment, there is provided a lawn mower barrier for restrictingautonomous lawn mowers to a designated area. The lawn mower barriercomprises an elongate, pliable barrier body with two terminal ends. Thebarrier body has a diameter between 5-30 cm and is a liquid proofcontainer comprising a hollow space. The terminal ends are configuredfor connection to each other to form a closed loop, the lawn mowerbarrier comprises a valve for filling the hollow space with a liquid.

According to another embodiment, the valve is provided at one of theterminal ends.

According to another embodiment, a valve is provided at both terminalends.

According to another embodiment, the lawn mower barrier comprises atleast one pressure sensor for detecting leakage from the lawn mowerbarrier.

According to another embodiment, the at least one pressure sensor isprovided at a terminal end.

According to another embodiment, the pressure sensor is in communicationwith a controller, and the controller is configured to trigger an alarmin case of a leakage from the barrier body.

According to another embodiment, the liquid is water.

According to another embodiment, the barrier body comprises arotationally symmetrical cross-section.

According to another embodiment, the lawn mower barrier furthercomprises a perimeter wire.

According to another embodiment, a plurality of lawn mower barriers canform a lawn mower barrier assembly.

There is also provided a method of restricting autonomous lawn mowers toa designated area, comprising the steps of placing at least one lawnmower barrier along at least a portion of the periphery of thedesignated area and filling the at least one lawn mower barrier with aliquid.

According to another embodiment the method further comprises the step ofconnecting the at least one lawn mower barrier end-to-end.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other characteristics will become clear from the followingdescription of embodiments, given as non-restrictive examples, withreference to the attached schematic figures.

FIG. 1 is a top view of a lawn mower barrier restricting movement ofautonomous lawn mowers to a designated area.

FIG. 2 is a side view of a lawn mower and a cross section of a lawnmower barrier filled with a fluid.

FIG. 3 illustrates a first embodiment of terminal ends of a lawn mowerbarrier connected to each other, and a pressure sensor.

FIG. 4 illustrates a second embodiment of terminal ends of a lawn mowerbarrier with valves and pressure sensors.

FIG. 5 illustrates a portion of an embodiment of a lawn mower barriercomprising a perimeter wire and a power outlet.

DETAILED DESCRIPTION

The following description may use terms such as “horizontal”,“vertical”, “lateral”, “upper”, “lower”, “inner”, “outer”, “forward”,“rear”, etc. These terms generally refer to the views and orientationsas shown in the figures and that are associated with a normal use of theinvention. The terms are used for the reader's convenience only andshall not be limiting.

Referring initially to FIGS. 1 and 2, a lawn 1 is illustrated withautonomous lawn mowers 2. A lawn mower barrier 3 is positioned along theperiphery of the lawn 1 to restrict movement of the autonomous lawnmowers 2 and provide a physical safety barrier in case the controlsystems of the autonomous lawn mowers 2 fail. A designated area 4 forthe autonomous lawn mowers 2 is thus defined by the lawn mower barrier3. The lawn mower barrier 3 prevents autonomous lawn mowers 2 fromleaving the designated area 4 and moving to another, unwanted areaoutside the lawn mower barrier 3. The unwanted area may be a runway atan airport, a motorway, or other area in which small, autonomousvehicles may pose a great danger if they enter.

The lawn mower barrier 3 comprises an elongate barrier body 5 with twoterminal ends 6 a,b. It is in this context understood that the barrierbody 5 thus has a length that is far greater than the width. Theterminal ends 6 a,b are configured to be connected to each other, suchthat the lawn mower barrier 3 forms a closed loop, as illustrated inFIG. 1. However, the terminal ends 6 a,b need not be connected to eachother, if the lawn mower barrier 3 is to cover only part of theperiphery of a designated area 4. If the lawn mower barrier 3 forms aclosed loop, the autonomous lawn mowers 2 are prevented from leaving thedesignated area 4 defined by the lawn mower barrier 3. The barrier body5 may be from a few meters long up to hundred meters and more.

The barrier body 5 is pliable, and may be static or flexible. Thebarrier body 5 comprises a hollow space 7 which extends along the lengthof the barrier body 5. The barrier body 5 may be formed similarly to ahose. As the barrier body 5 is pliable, it may easily be collapsed whennot in use. The lawn mower barrier 3 can as such be rolled up and storedin a rolled-up position. This allows for both easy installation andremoval, transportation and storage of the lawn mower barrier 3.

The terminal ends 6 a,b may be angled, or may be connected to an angledelement, such that a defined angle may be introduced to the lawn mowerbarrier 3. E.g. if a 90° bend is desirable, in order to conform the lawnmower barrier 3 to a specific shape of the designated area 4, the 90°bend could be established at the connection between two terminal ends ofa lawn mower barrier.

In order to increase the volume and the mass of the barrier body 5, andmake it firm and capable of withstanding an impact with an automatedlawn mower 2, the hollow space 7 of the barrier body 5 is filled with afluid, as illustrated in FIG. 2. The barrier body 5 is thus a fluidproof container. The fluid may be a liquid such as water, or otherlow-cost and easy accessible fluid. The hollow space 7 may be filledwith a fluid at a terminal end 6 a or 6 b, through a valve. A valve forfilling the hollow space 7 may as such be positioned anywhere on thelawn mower barrier 3. The lawn mower barrier 3 may be filled with afluid prior to connecting the terminal ends 6 a,b to themselves. Whenfilled, the pressure from the fluid exerted on the barrier body 5 makesit expand into a shape determined by the construction of the barrierbody 5, and the lawn mower barrier 3 is thus established with a givenwidth and height of the barrier body 5. A lawn mower barrier 3 filledwith a fluid also adds weight to the barrier, such that the lawn mowerbarrier 3 will adapt to the bumps and contours of the ground and thusprovide a very adaptable lawn mower barrier 3. A lawn mower barrier 3filled with a fluid will also make the lawn mower barrier rigid andresilient.

The fluid may be coloured, such that leakage is easy to detect. Thefluid inside the lawn mower barrier 3 may also be fluorescent in orderto enhance probability of detecting a leakage before the integrity ofthe barrier is compromised. The lawn mower barrier 3 may in analternative embodiment be filled with a foam or similar substance.

The terminal ends 6 a,b of a lawn mower barrier 3 may be connected toterminal ends of other lawn mower barriers 3, such that a plurality oflawn mower barriers 3 may be serial-connected to each other to form abarrier assembly of any length. A lawn mower barrier assembly thuscomprises a plurality of lawn mower barriers 3, connected end-to-end, inorder to define designated areas of various perimeter length. The lawnmower barriers 3 may have barrier bodies 5 of individual length andcross-section, meaning they could be different in length andcross-section, but may also be identical. The lawn mower barriers 3 of alawn mower barrier assembly may be filled with a fluid prior to beingconnected to each other.

The barrier bodies 5 can also be provided in different lengths, and withdifferent cross-sections. A lawn mower barrier 3 may comprise a barrierbody 5 of a given length and cross-section, and at the terminal ends 6a,b it could be connected to other lawn mower barriers with differentlengths and different cross-sections. Such variations allows a barrierconsisting of a plurality of lawn mower barriers 3 to be adapted to theground it is placed on.

Because the barrier body 5 is pliable and filled with a fluid, a segmentof the lawn mower barrier 3 may be compressed and deformed if subjectedto a sufficiently heavy load, for thereby to return to its originalshape as the fluid pressure expands the barrier body 5 as the heavy loadis removed. As such, the lawn mower barrier 3 allows large vehicles tocompress and pass by the barrier, while autonomous lawn mowers 2 are notsufficiently heavy or have enough clearance to the ground to compressand pass by the lawn mower barrier 3. Such large vehicles may bepersonal transportation such as cars and trucks, and airplanes moving onthe ground, etc. As the wheel of e.g. a car passes the lawn mowerbarrier 3, the weight of the car temporarily compresses the lawn mowerbarrier 3 flat towards the ground, but as the wheel of the car passes,the lawn mower barrier 3 retains its original shape.

The cross-section of the lawn mower barrier body 5 could be basicallycircular, as illustrated in FIG. 2. A circular, angular or otherwiserotationally symmetrical cross-section prevents unwanted effects relatedto the lawn mower barrier 3 being positioned up-side down or in othernon-optimal positions. A rotationally symmetrical cross-sectionsimplifies installation and removal of the lawn mower barrier 3 as itcan be rolled out and rolled in, without consideration as to whichorientation it has when it is rolled out onto the ground. The weight ofthe lawn mower barrier 3 and the fluid inside it keep the lawn mowerbarrier 3 securely positioned on the ground. As the lawn mower barrier 3is placed on top of the ground, and does not need to be secured to theground, it can be placed just as easily on lawn as on tarmac, rocks,etc. where a traditional fence or other barrier could be both difficultand undesirable to set up and secure.

A barrier body 5 with a circular cross section could have a diameter ofbetween 5-50 cm. The diameter of the barrier body 5 may be between 10-40cm, and more preferably between 5-30 cm. A cross section of theindicated dimensions is sufficient to prevent autonomous lawn mowers topass by the lawn mower barrier 3, while both airplanes moving on theground and personal vehicles can pass by the barrier withoutcompromising the safety of the vehicle or the barrier.

A barrier body 5 may be made from materials such as rubber, PVC,Polyurethane, Neoprene and silicon, or it could be made from a fabricmaterial, or a combination. The barrier body could also be reinforcedwith fabrics or fibres such as glass fibre and Kevlar. Reinforcementscould add strength and durability to the body 5, in order to reduce theeffects of wear and tear and increase the lifetime of the lawn mowerbarrier 3.

Referring now to FIG. 3, a first embodiment of terminal ends 6 a,b of alawn mower barrier 3 connected together is illustrated. Although notillustrated, one or both of the terminal ends 6 a,b may comprise a valvethrough which fluid could be fed to the barrier body 5. The connectioncomprises a connector 8 between the two terminal ends 6 a,b. Asexplained previously, the terminal ends 6 a,b may be terminal ends ofthe same lawn mower barrier body, or it may be terminal ends from twoseparate barrier bodies 5, if a lawn mower barrier assembly comprisesmore than one lawn mower barrier 3. The connector 8 is in theillustrated embodiment a pressure-tight seal between the terminal ends 6a,b, and the terminal ends 6 a,b are secured to each other and theconnector 8 with a pin and chain. The terminal ends 6 a,b mayalternatively be secured directly to one another without a separateconnector 8 by means of threaded connections, non-threaded gendercouplers or genderless couplers, flanged couplings, and similar.

The lawn mower barrier 3 may comprise a pressure sensor 9. In theillustrated embodiment, the pressure sensor 9 is part of the connector8, but the pressure sensor 9 may also be an integrated part of theterminal ends 6 a or 6 b of the lawn mower barrier 3, or even a part ofthe barrier body 5. A lawn mower barrier assembly comprising a pluralityof lawn mower barriers 3 may thus comprise several pressure sensors 9.The pressure sensor 9 is configured to monitor the pressure inside thelawn mower barrier 3, and transmit status or deviations from apredetermined level to a controller 10. The pressure sensor 9 may be incommunication with and transmit to the controller 10 over the air or viacable, depending on location and equipment.

If the lawn mower barrier 3 is compromised, i.e. a leakage occurs andthe lawn mower barrier 3 is possibly not able to prevent autonomous lawnmowers to pass by it, the pressure sensor 9 will detect a pressure dropthat is transmitted to the controller 10. The controller 10 may respondby triggering an alarm and automatically shut down the autonomous lawnmowers, to prevent them from accidentally leaving the designated areadefined by the damaged lawn mower barrier 3. A notification of thecompromised barrier could also be transmitted to e.g. mobile phones. Thepressure inside a lawn mower barrier 3 could be e.g. between 0.5-1.5bar, and a threshold for the controller 10 could be set equally. Thepressure sensor 9 or controller 10 may be adjusted such that thepressure sensor system does not shut down the autonomous lawn mowers incase of a brief pressure increase, e.g. due to a heavy vehicle passingby and temporarily deforming the lawn mower barrier 3. The pressuresensor(s) 9 and controller(s) 10 could be configured such that upon ashort but sudden pressure increase, the system could notify that avehicle has likely passed the lawn mower barrier 3, and as such enteredor left the designated area.

Referring now to FIG. 4, a second embodiment of terminal ends 6 a′,b′ ofa lawn mower barrier 3′ is illustrated. The terminal end 6 a′ comprisesa valve 12 a, and another terminal end 6 b′ comprises another valve 12b. As such, the lawn mower barrier 3′ may be filled from each terminalend, which may be far apart. Also, when placing the lawn mower barrier3′, there is no need to take into account the orientation, i.e. whichterminal end is positioned where, as the lawn mower barrier 3′ can befilled with a fluid at both terminal ends 6 a′,b′. The terminal ends 6a′,b′ may be terminal ends of the same lawn mower barrier body, or itmay be terminal ends from two separate barrier bodies, if a lawn mowerbarrier assembly comprises more than one lawn mower barrier 3′.Alternatively, the valve 12 a and/or the valve 12 b could be positionedanywhere on the lawn mower barrier 3′. The illustrated valves 12 a,b arevalves of the manual type, but any type of valve configured for fillinga fluid may be utilised. When the lawn mower barrier 3′ is to beremoved, the valves 12 a,b can be opened in order to empty the fluidfrom the barrier.

The terminal ends 6 a′,b′ need not necessarily be in physical contact,but could be secured to each other by a connection element 11 such as awire, a chain, or similar. The terminal ends 6 a′,b′ may alternativelybe secured directly to one another without a connection element 11 bymeans of threaded connections, non-threaded gender couplers orgenderless couplers, flanged couplings, and similar.

The lawn mower barrier 3′ comprises two pressure sensors 9 a′,b′. In theillustrated embodiment, both terminal ends 6 a′,b′ of the lawn mowerbarrier 3′ comprises a pressure sensor 9 a′,b′. In high-risk areas,there might be a demand for a second pressure sensor, and the terminalends 6 a′ and 6 b′ might be similar in design, such that each terminalend 6 a′,b′ thereby comprises a pressure sensor 9 a′,b′. The pressuresensors 9 a′,b′ are configured to monitor the pressure inside the lawnmower barrier 3′, and transmit status or deviations from a predeterminedlevel to a controller 10′. The pressure sensors 9 a′,b′ may be incommunication with and transmit to the controller 10′ over the air orvia cable, depending on location and equipment.

If the lawn mower barrier 3′ is compromised, i.e. a leakage occurs andthe lawn mower barrier 3′ is possibly not able to prevent autonomouslawn mowers to pass by it, the pressure sensors 9 a′,b′ will detect apressure drop that is transmitted to the controller 10′ that may respondsimilarly to that described with reference to the first embodiment.

Referring now to FIG. 5, an embodiment of a lawn mower barrier 3comprising a perimeter wire 13 is illustrated. A perimeter wire is awire that is typically positioned around the perimeter of a designatedarea for lawn mowers. The perimeter wire is commonly dug into the groundand restricts the lawn mowers to the designated area. In order to cutthe lawn evenly along the perimeter, lawn mowers may also every now andthen be programmed to move along the perimeter wire. A lawn mowerbarrier 3 may comprise such a perimeter wire 13 to additionally indicatethe perimeter of a designated area. The perimeter wire 13 may extendalong the length of the lawn mower barrier 3, and may be connected to anelectric supply 14.

The lawn mower barrier 3 may be connected to an internal or externalbattery (not shown), that may in turn be connected to and powered by asolar cell or equivalent power source. The lawn mower barrier 3 may assuch operate off-grid. Alternatively, the electric supply 14 may beconnected to a power grid. In the illustrated embodiment, the electricsupply 14 is positioned at a terminal end 6 a of the barrier body 5, butit may as such be positioned anywhere on the lawn mower barrier 3. Poweroutlets 15 may additionally be positioned along the perimeter wire 13and/or the length of the lawn mower barrier 3. The lawn mower barrier 3may as such distribute power to various devices connected to the poweroutlets 15. The power outlets 15 may be used to connect e.g. lights,speakers and various means for keeping birds away along the length ofthe lawn mower barrier 3.

Instead of light, the lawn mower barrier 3 may also be provided withe.g. luminescent paint or details in order to increase visibility in thedark.

In order to scare birds and rodents away, the lawn mower barrier 3 couldalso be used to transmit e.g. vibrations. Such vibrations could beinduced anywhere along the length of the barrier and be transmittedalong the length of the barrier body 5 by the barrier body 5 itself orby vibrating the liquid contained inside the hollow space. Suchvibrations could generate sound and be transmitted into the ground,effectively annoying both nearby birds and rodents.

A transmitter 16 for enhancing the signals of the positioning system(GPS) used to navigate the lawn mowers may also be provided on the lawnmower barrier 3. Such a transmitter 16 may be positioned at a terminalend 6 as illustrated, or several transmitters 16 could be distributedalong the length of the lawn mower barrier 3.

1. A lawn mower barrier for restricting autonomous lawn mowers to adesignated area, comprising: an elongate, pliable barrier body with twoterminal ends, wherein the barrier body has a diameter between 5-30 cmand is a liquid proof container comprising a hollow space; the terminalends are configured for connection to each other to form a closed loop;the lawn mower barrier comprises a valve for filling the hollow spacewith a liquid.
 2. The lawn mower barrier of claim 1, where the valve isprovided at one of the terminal ends.
 3. The lawn mower barrier of claim1, where a valve is provided at both terminal ends.
 4. The lawn mowerbarrier of claim 1, further comprising at least one pressure sensor fordetecting leakage from the lawn mower barrier.
 5. The lawn mower barrierof claim 4, where the at least one pressure sensor is provided at aterminal end.
 6. The lawn mower barrier of claim 4, where the at leastone pressure sensor is in communication with a controller, and thecontroller is configured to trigger an alarm in case of a leakage fromthe barrier body.
 7. The lawn mower barrier of claim 1, where the liquidis water.
 8. The lawn mower barrier of claim 1, where the barrier bodycomprises a rotationally symmetrical cross-section.
 9. The lawn mowerbarrier of claim 1, further comprising a perimeter wire.
 10. A lawnmower barrier assembly comprising a plurality of lawn mower barriersaccording to claim
 1. 11. A method of restricting autonomous lawn mowersto a designated area, characterized in comprising the steps of: i.placing at least one lawn mower barrier according to claim 1 along atleast a portion of the periphery of the designated area, ii. filling theat least one lawn mower barrier with a liquid, where steps i and ii maybe performed in any sequence.
 12. The method of claim 11, furthercomprising the step of connecting the at least one lawn mower barrierend-to-end.